Clinton victories in Texas and Ohio give McCain time to craft his message

As for McCain, the Tuesday primaries handed him a majority of the delegates needed to secure the Republican nomination, prompting former Arkansas Gov. Mick Huckabee to abandon his presidential bid and President Bush to give McCain his official endorsement. Despite the president's low approval rating, his endorsement will help unite the party and win over conservatives skeptical of the independent-minded senator, analysts say.

"John showed incredible courage, strength of character, and perseverance in order to get to this moment, and that's exactly what we need in a president – somebody who can handle the tough decisions, somebody who won't flinch in the face of danger," Mr. Bush said Wednesday, appearing with McCain in the White House Rose Garden.

McCain's return to Washington was a victory lap of sorts after a bruising 16-month Republican presidential primary. He was visiting not only the White House he hopes to occupy but also the Republican National Committee headquarters that he essentially assumes control of now that he's the expected GOP nominee.

Obama's streak ends

With Tuesday's three wins – in Ohio, Texas, and Rhode Island – Clinton reversed an 11-contest losing streak. The seven weeks until the next major primary, in Pennsylvania on April 22, buy her ample time to raise money, sharpen attacks on her rival, and convince the elected officials and party leaders known as superdelegates that she is still a contender.